Well, I have discovered that if I put the keyswitch directly on the actual synth track, it works - but only if I transpose it up an octave. For example, for violins, G1=pizzicato. I have to put G2 in for it to switch. note that this is only for the second violins, the other strings are working OK. I think I can solve that with some octave setting adjustments. I've run into that before.
I'm going to explore this some more and see if this can be a viable solution for all the strings. If so, I can use the synth track as the midi track, which I can delete. If I wanted, I could actually use only the synth track, as Cakewalk lets you use it as if it were an inst. track, complete with staff view so you can see the notes. Currently, I use a separate midi track for the keyswitches, for reasons of clarity (the keyswitch notes don't mess up the actual musical notes).